Coating for reducing operating temperatures of chamber components of a coating apparatus

Abstract

A component for use in a high-temperature environment such as the coating chamber of a PVD apparatus. A reflective coating on the component serves as a barrier to radiant heat transfer to the component by reflecting thermal radiation. The coating comprises at least one pair of reflective layers, each layer being formed of a material that is essentially transparent to electromagnetic wavelengths of between 500 and 3000 nanometers (nm). In addition, the material of the outermost layer of the pair has a higher index of refraction than the material of the other layer of the pair.

What is claimed is:  
     
       1. A coating chamber component of a coating apparatus, the component comprising a thermally-reflective coating on a surface thereof, the coating comprising at least two adjacent pairs of layers formed of materials that are substantially transparent to infrared radiation at a predetermined wavelength, an outermost layer of each of the pairs of layers being formed of a material having a higher index of refraction than an innermost layer of the same pair of layers, the innermost layer of at least one of the pairs of layers being thicker than the outermost layer of the same pair of layers, the innermost layer of a second of the pairs of layers being thinner than the outermost layer of the same pair of layers. 
     
     
       2. A coating chamber component as recited in claim  1 , wherein the component with the coating has an average reflectivity of at least 90% for electromagnetic wavelengths of about 380 to about 1500 nanometers. 
     
     
       3. A coating chamber component as recited in claim  1 , wherein the outermost layer of the pair of layers is a material selected from the group consisting of titania, tantala, zirconia and niobium oxide, and wherein the innermost layer of the pair of layers is a material selected from the group consisting of refractory fluorides, silica and alumina. 
     
     
       4. A coating chamber component as recited in claim  1 , wherein the combined thickness of the innermost layers of the pairs of layers is greater than the combined thickness of the outermost layers of the pairs of layers by a factor inversely proportional to their indices of refraction. 
     
     
       5. A coating chamber component as recited in claim  1 , wherein the coating has a thickness of about 100 to about 4000 nanometers. 
     
     
       6. A coating chamber component as recited in claim  1 , wherein the innermost layer of each of the pairs of layers has an index of refraction of about 1.25 to about 1.7, and the outermost layer of each of the pairs of layers has an index of refraction of about 2.0 to about 2.3. 
     
     
       7. A coating chamber component as recited in claim  1 , wherein the materials of the pairs of layers are substantially transparent to electromagnetic wavelengths of between 500 and 3000 nanometers. 
     
     
       8. A coating chamber component as recited in claim  1 , wherein the coating comprises sixteen to fifty alternating layers of two materials that are substantially transparent to infrared radiation at wavelengths of between 500 and 3000 nanometers. 
     
     
       9. A coating chamber component as recited in claim  1 , wherein the coating comprises sixteen layers of silica alternating with sixteen layers of titania, an innermost layer of the coating being silica and an outermost layer of the coating being titania, the layers of silica having thicknesses of, starting with the innermost layer of the coating and concluding with a silica layer adjacent the outermost layer of the coating, about 187.27, 344.10, 197.91, 166.05, 153.74, 85.10, 131.15, 134.27, 26.22, 22.37, 111.99, 47.77, 147.85, 95.29, 91.91 and 323.08 nm, respectively, and the layers of titania having thicknesses of, starting with a titania layer adjacent the innermost layer of the coating and concluding with the outermost layer of the coating, 138.00, 119.81, 120.25, 91.16, 73.03, 71.10, 121.40, 184.65, 136.39, 79.27, 68.03, 58.36, 107.91, 51.64, 39.22 and 61.57 nm, respectively. 
     
     
       10. A coating chamber component as recited in claim  1 , wherein the component is configured to manipulate an article coated in the coating apparatus. 
     
     
       11. A coating chamber component as recited in claim  1 , further comprising a physical vapor deposition apparatus having a coating chamber in which the component is mounted. 
     
     
       12. A coating chamber component of a coating apparatus, the component comprising a thermally-reflective coating on a surface thereof, the coating comprising a plurality of layers in which layers of a first material alternate with layers of a second material so as to define adjacent pairs of layers of the first and second materials, the first and second materials being substantially transparent to infrared radiation at a predetermined wavelength, the second material having a higher index of refraction than the first material, an innermost layer of each of the pairs of layers being formed of the first material and an outermost layer of each of the pairs of layers being the second material, the innermost layers of most of the pairs of layers being thicker than the outermost layers of the pairs of layers, the innermost layer of at least one of the pairs of layers being thinner than the outermost layer of the at least one of the pairs of layers to suppress optical harmonics in the coating, the combined thickness of the innermost layers being greater than the combined thickness of the outermost layers by a factor inversely proportional to their indices of refraction. 
     
     
       13. A physical vapor deposition apparatus comprising: 
       a component configured to manipulate an article being coated with the apparatus; and  
       a thermally-reflective coating on a surface of the component, the coating comprising at least two adjacent pairs of layers formed of metal oxides that are substantially transparent to electromagnetic wavelengths of between 500 and 3000 nanometers, an outermost layer of each of the pairs of layers having a higher index of refraction than an innermost layer of the same pair of layers, the innermost layer of at least one of the pairs of layers being thicker than the outermost layer of the same pair of layers, the innermost layer of a second of the pairs of layers being thinner than the outermost layer of the same pair of layers, the combined thickness of the innermost layers being greater than the combined thickness of the outermost layers by a factor inversely proportional to their indices of refraction.  
     
     
       14. A physical vapor deposition apparatus as recited in claim  13 , wherein the component with the coating has a reflectivity of at least 90% for electromagnetic wavelengths of about 380 to about 1500 nanometers. 
     
     
       15. A physical vapor deposition apparatus as recited in claim  13 , wherein the coating has a thickness of about 100 to about 4000 nm. 
     
     
       16. A physical vapor deposition apparatus as recited in claim  13 , wherein the coating comprises a first layer adjacent the surface of the component, a second layer on the first layer, a third layer on the second layer, and a fourth layer on the third layer, the first and third layers being formed of silica, the second and fourth layers being formed of titania. 
     
     
       17. A physical vapor deposition apparatus as recited in claim  13 , wherein the coating comprises sixteen to fifty layers of materials that are substantially transparent to infrared radiation at wavelengths of between 500 and 3000 nanometers. 
     
     
       18. A physical vapor deposition apparatus as recited in claim  13 , wherein the coating comprises sixteen layers of silica alternating with sixteen layers of titania, an innermost layer of the coating being silica and an outermost layer of the coating being titania, the layers of silica having thicknesses of, starting with the innermost layer of the coating and concluding with a silica layer adjacent the outermost layer of the coating, about 187.27, 344.10, 197.91, 166.05, 153.74, 85.10, 131.15, 134.27, 26.22, 22.37, 111.99, 47.77, 147.85, 95.29, 91.91 and 323.08 nm, respectively, and the layers of titania having thicknesses of, starting with a titania layer adjacent the innermost layer of the coating and concluding with the outermost layer of the coating, 138.00, 119.81, 120.25, 91.16, 73.03, 71.10, 121.40, 184.65, 136.39, 79.27, 68.03, 58.36, 107.91, 51.64, 39.22 and 61.57 nm, respectively.